Snubber for quick break attachment



Feb. 1o, 1959 w. B. KELLY 2,873,325

SNUBBER FOR QUICK BREAK ATTACHMENT Filed llay 14, 1954 Wav-fe nu Y ffm `been caused in instances when the main 2,873,325 y SNUBBER ron QUICKBREAK ATTACHMENT Walter B. Kelly, New Stanton, Pa., assignor to I-T-E Circuit Breaker Company, PhiladelphiaPa., a corpora-U i tion of Pennsylvania t l Application May 14, 1954, Serial `No.` 429,916

' 6 Claims. (ci. 20o-4s) This invention relates to arcing horns for electrical disconnect switches of the outdoor type and more particularly to `means for snubbing the rebound of rapidly moving arcing horns `associated with such switches.

In my copending application Serial No. 429,873, tiled May 14, 1954, there is shown and described a tapered and tubular arcing horn capable of extremely high contact breaking speeds, approximately 90 feet per second 'being developed in the course of its breaking motion away from itsstationar-y contact element. In the course of experimentation with this rapidly `acting horn, `a problem arose by virtue of the possibility of resilient rebound of the horn toward its stationary contact element. In fact, one of the problems of the industry` in connection with quick-break" horns has been the danger of rebound whichmay be suiciently extreme to cause restking ofthe arc, unless the movable switch `arm itself has been moved to such a position in the interval of time in which the horn acts as to prevent the horn from rebounding all the way back to arc restriking position. Thus, failure of proper operation has switch was not operated at a suitablyhigh rate of speed.

Accordingly, it is `an object of my invention to provide means for snubbing a high-speed arcing horn in such ya manner as to prevent rebound and restriking of the arc.

It is another object of my invention to provide a simple and economical construction which will stand up` under extreme weather conditions toperforrn its designed purpose.

It is a further object of my invention to provide a snubber construction capable of capturing and holding the fast-moving horn until vibration has nearly ceased.

It is still another object of my invention to provide a horn and snubber `arrangement such that the amount of gap between the moving horn and the stationary element fastened to the switch blade is practically independent of speed of operation of the switch blade.

Brieiiy, my invention envisages a snubber construction such that the plane of motion of the moving horn is changed from the original plane, in which it breaks away from the stationary element, into a plane nearly normal or at least into a plane at a substantial angle to the original plane.

This does not reduce the air gap and results in very rapid dissipation of energy in the moving arcing horn. It is to be particularly noted that the vibration resulting in the dissipation of energy, that is, the kinetic energy of the arcing horn, taking place in aplane nearly normal to the original plane of motion, not only consumes such kinetic energy rapidly, but eliminates any danger of the reduction of the air gap between the horn and the stationary element from which it has 'broken contact. Thus, if the horn were permitted to vibrate in the plane of motion, there would be danger of restriking the arc. Where, however, vibration takes place in a plane at a substantial angle to the original plane of motion, there is no danger of restriking the arc.

A particular feature of my invention resides in a novel arent l.

construction wherein the arcing horn is factually momentarily caught within the snubber structure to materially reduce or restrict the vibration amplitude.` This enormously increases the frequency of vibration of the horn and to that extent more readily diminishes the vibratory energy. Further, by placing the snubber on the moving switch arm which carries the arcing horn in such a position that the horn strikes the snubber when it has travelled a quarter cycle of its natural period, enough kinetic energy remains in thehorn to drive it into a loop structure formed as part of the snubber where it is trapped and permitted to vibrate harmlessly.

My invention is applicable to either horizontal or vertical break switches as will be readily understood from the disclosure which now follows, in conjunction with the appended drawing in which: t

Figure 1 is a plan view of a horizontally acting switch."

arrangement 16 in a manner heretofore disclosed in my` copending patent `application Serial No. 429,873, filed May 14, 1954. The horn 14 may be of a tapered, tubular type as described in the foregoing application, but it will be understood that any suitable resilient horn may be utilized for the purposes ofthe present invention.

A stationary arc horn 20, with which the horn 14 is normally in contact, is provided, secured in a conven` tional manner to the stationary switch element 22. .It

will be appreciated by reference to Figure 1, wherein is` shown in dash lines 14 and 14" the positions of the ele`-v` ments 10 and 14 just before the tip of the horn leaves the stationary element 20, that considerable rebound can ,normally be expected after the horn has completed its full half cycle of outward travel.

In order to prevent such rebound and possible.restrik-` ing of the arc, I provide a dampener or snub'ber 24 such as shown in Figure 3. The snubber 24 may be secured as by a U-bolt 26 to the switch blade 10 and is shaped so as to have aY sloping portion 28 rising from a portion 30 which is substantially normal to the plane of travel ot` the horn 14. The portion 28 may make any suitable angle with portion 30; I have found an angl-e of about designated as 29 on Figure 3 to be satisfactory thus making a 55 angle with the plane of motion of horn 14, as designated by 29a. The relationship of horn 14 with portion 28 when the switch is either open. or closed is as shown on Figure 3.

The sloping portion 28 terminates in a loop 32 having an opening 34 which has a gap of suitable width as to permit entry into the loop of the horn 14.

In operation, at the time the horn leaves the stationary element 20, it will whip in a direction as shown by the arrow in Figure l at extremely high speed and will strike the sloping portion 28. This occurs as will be seen from the layout in Figure l when the horn completes approximately one quarter of its full cycle of travel, it being understood that a full cycle would carry the horn from the position shown in Figure 1 to a substantially opposite position, with reverse curvature, and then back again to a somewhat .lesser extent to the original position. When, however, the horn strikes the surface 28, it is cammed or deected upwardly through the gap 34 `and into the loop 32 where for all practical purposes it is trapped, and its natural period of vibration is then considerably increased i as it rebounds back and forth in more or less vertical di- Patented Feb. 10, 1959;`

aser-rees ingly, the energy of the vibrating horn is rapidly spent in a ricocheting motion and there is no danger of its returning to restrike the arc. After vibration has ceased the horn', by `virtue of its resiliency, will straighten out toreleaseitself from the loop.

Preferably the snubber is placed on arm at 'apoint slightly Vpreviousto that point where the horn would have travelled a quarter cycle of its natural period. It will, however, `be understood that exact positioning of the snubber may vary as suits a certain switch and horn construction. Y

In the form of the invention shown in Figure 4, a substantiallyoperative modification is disclosed for a snubber having the Vertical-portion 40, the sloping portion 42, and a flange 44 bent at substantially right angles to the sloping portion 42. In this modification, the horn 14 is deflected upwardly along the sloping portion 42 until it strikes the ange 44. This absorbs a considerable amount of the horn energy and the coaction of the snubber portions 42 and 44result in a change of direction of vibration of the horn in `a plane substantially angularly related to the plane of original travel e. g., 55 relationship. Accordingly, the horn is no longer capable of reversing itself in the planeof original motion and thereiby danger of restriking the arc is eliminated.

I v.am aware that my invention is susceptible of considerable variation without departing from the true spirit thereof and accordingly I do not seek to be limited to the particular illustration herein given, except as set forth in `the appended claims.

Iclaim:

1. In f a switch arrangement comprising a llexible arcing horn, a snubber for said horn comprising an element disposed at an angle of less than 90 to the normal path of motionof said horn, so as to change the plane of motion of g said horn at a predetermined point in the travel thereof.

2. jIn a switch arrangement comprising a flexible arcing horn, v.a snubber for said horn comprising an element disposed at an angle of less than 90 to the normal path of motion of said horn, soas to change the plane of motion of said horn-at a predetermined point in the travel thereof, said snubber including an abutment carried by said elcment and disposedv to be struck `by said horn in travelling along said angularly disposed element.

4. In a switch arrangement, Ia movable switch arm, aA

flexible arcing horn carried by said switch arm, a snubber element carried by said switch arm engageable by said arcing horn when said horn is`in motion after being flexed during the course of opening of said switch, said snubber element having `a portion disposed at an angle of at least 45 and less than 90 to the path of motion of said horn, said portion being disposed to .be struckby said horn.

5. In a switch arrangement, a movable switch arm, a

exible arcing horn carried by said switch farm, a snubber element carried by said switch arm engageable by said arcing horn when said horn is in motion after being flexed during the course of opening of said switch, said snubberl element having a portion disposed at an angle of at least 45 to the pathof motion of said horn, said portion being disposed to be struck 'by said horn, saidfsnubber comprising a loop like structure having an opening adjacentfsaid angularly disposed portion whereby said horn may drive itself into said loop for entrapment therein.

-6. A combination of a movable switch arm, a resilient arcing horn carried thereby, and a snubber carriedthereby; vsaid snubber being disposed at an angle less than to the normal path of motion of said horn so as toire struck by said arcing horn during the course of travel thereof when said switch arm is actuated to disconnect from .said stationary contact; said snubber being constructed to prevent rebound of said resilient arcing horn.

References Cited in the le of this patent UNITED STATES PATENTS Schultz et al. "Apr, 20,1943 Samuel et al. Feb. 26,1957 

